The field of the invention relates to correlation of a data matrix of interest with a data reference for image matching or matrix location purposes.
In the field of information-handling or data storage and retrieval, it is often convenient to represent a body of related data relevant to a subject or parameter of interest, as a two-dimensional data matrix, in which a first variable corresponding to the state of the parameter of interest is indicated as a function of two other related parameters, represented as two mutually orthogonal dimensions defining the plane of the data matrix. Such parameter of interest may represent an intensity or magnitude which varies as a function of position in a plane or selected area. The parameter may even be only two-state or binary coded such as, for example, a black and white image.
In the field of data correlation or image matching, the prior art has endeavored to compare the image of an area or matrix of interest with a reference image or matrix which has involved the testing and correlation of each of the data elements of the data matrix of interest over the entire reference matrix. Such a technique requires a large amount of data processing capacity in terms of computer hardware, software, or both, and may require substantial processing time. The required processing capacity and time, of course, are increased as the size of the data matrix is increased or the desired image resolution improved. A view of such prior art spatial discrimination techniques is described in U.S. Pat. No. 3,444,380.
The process of image matching has a number of potential uses, such as in the matching of ground-mapping radar data with a reference map for terminal guidance purposes. The ability to automatically perform such a function removes the element of human skill in performing such function, as to allow such terminal guidance procedure for unmanned vehicles. However, the necessary data processing capacity and speed required for such a mission have been difficult to achieve in a limited equipment package which is useful and practical for airborne applications.